Mandarin tree named ‘Valley Gold’

ABSTRACT

A new variety of mandarin ( Citrus L. ) designated ‘Valley Gold’ is described. The novel characteristics of the fruit include late onset of maturity of fruit, a distinct tougher rag and rind, and a darker external orange color (R.H.S. 28A) as compared to known varieties.

Botanical/commercial classification: (Citrus reticulata), new hybridmandarin variety.

Variety denomination: ‘Valley Gold’.

BACKGROUND OF THE INVENTION

‘Valley Gold’ is a hybrid of Citrus reticulata variety Ellendale (notpatented) (the seed parent) and an unpatented mandarin hybrid varietyRobin (not patented) (the pollen parent). In 1980, pollen from ‘Robin’was applied by hand to the stigmas of ‘Ellendale’. The resulting fruitswere collected in June 1981 whereafter seeds from each fruit wereextracted and irradiated and thereafter planted in 1982. The resulting73 seedlings were transplanted to a breeding orchard situated in Addo,in the Eastern Cape province of the Republic of South Africa (globalpositioning satellite co-ordinates 25°42′E; 33°34′S). These seedlingswere not grafted and were grown on their own roots. Due to the so-calledjuvenility phenomenon in citrus trees as is known in the art, treesresulting from these transplanted seedlings only bore fruit in 1992.These trees were then evaluated for fruit quality traits. Based on theresults of this evaluation, six of the aforementioned trees wereselected for further evaluation, of which one of these selectionsresulted in the present ‘Valley Gold’ variety. Valley Gold was madesubject of a South African Plant Breeders' Rights application in January2000. This application was subsequently granted in 2004 under number ZA20043214.

Fruit quality, and the time of fruit maturity (mid to end July), makesthis selection a good candidate for the European market.

Severe to mild fruit splitting may occur in March or April, depending onrind thickness. However, crop load is still acceptable after split fruithas been dropped. Additionally, trees tend to be alternate-bearing.

‘Valley Gold’ was first asexually propagated in Addo, South Africa in1995 when buds were collected from a hybrid seedling designatedX83-2505/5, and then budded onto ‘Carizzo citrange’ rootstocks. Tentrees of ‘Valley Gold’ were planted in the field in September 1996 fordescription purposes. All characteristics of the original tree and itsfruit as determined and described appear to be transmitted throughsucceeding asexual propagations. While ‘Valley Gold’ has been propagatedand grown on ‘Carizzo citrange’ rootstock, no incompatibility or otherrootstock related problems have been observed. The mother tree isgrowing on its own roots and is currently (2008) 24 years old. Althoughthe tree condition is beginning to decline, the fruit quality is andalways has been good.

Further, ‘Valley Gold’ has been cleansed of all viruses and viroids byshoot-tip grafting (STG), followed by pre-immunization with Citrustristeza virus LMS6. This was done through a regulated process, whichinvolves taking vegetative buds from the mother tree and introducingsame into the South African Citrus Improvement Scheme. In this process,plant material is shoot-tip grafted to provide a virus-free source ofbud wood material. Material so obtained is then pre-immunized with amild strain of the aforementioned Citrus tristeza virus, followed by acertification by the Citrus Foundation Block.

The applicant is aware of U.S. Plant Pat. No. 16,289 ('289). The presentvariety is distinguishable over '289 in that, inter alia, not only isthe present variety diploid whereas '289 is triploid, but also therespective rind colors differ.

BRIEF SUMMARY OF THE INVENTION

In this specification, all major color code designations are made withreference to the R.H.S. Colour Chart (1986) as provided by The RoyalHorticultural Society of Great Britain.

This invention relates to a new and distinct variety of mandarin (Citrusreticulata), presently named ‘Valley Gold’ the novel characteristics ofwhich, under the local South African evaluation conditions, resideparticularly in the late onset of maturity of the fruit, as well as in atougher rag and rind, and a darker orange external color of the rind,(Royal Horticultural Society of Great Britain RHS 28A).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: is a photograph showing an entire tree;

FIG. 2( a): is a photograph showing the crop load potential of ‘ValleyGold’ after fruit split has been dropped;

FIG. 2( b): is a photograph of the fruit showing the obloid shape andthe dark orange (RHS 28A) rind color;

FIG. 3: is a further photograph showing details of ‘Valley Gold’ fruit:viewed from the side, apex, base and including a cross section through afruit, illustrating the color (RHS 28A) of the rind;

FIG. 4( a): is a photograph of the stem when viewed from a firstperspective;

FIG. 4( b): is a photograph of the stem when viewed from a secondperspective;

FIG. 5: is a close-up photograph showing several leaves of ‘ValleyGold’, illustrating the sizes and shapes of the leaves, including thevenation thereof;

FIG. 6: is a photograph showing florescence; and

FIG. 7: is a schematic illustration of the pedigree of ‘Valley Gold’.

DETAILED BOTANICAL DESCRIPTION

The below detailed description is based on 4 to 6, and 11 year oldtrees, unless otherwise specifically stated to the contrary.

-   Tree: ‘Valley Gold’ trees are moderately spreading with small    thorns, although fruit-bearing branches tend to become thornless.    Tree vigor and density is medium. The rootstock compatibility with    ‘Carizzo citrange’ is medium as observed and indicated by stem    measurements. Also of significance is the fact that the ‘Valley    Gold’ mother tree has thorns on its main branches, whereas the    daughter trees are totally without thorns. The young trees in the    nursery do not have any thorns and this is probably due to the fact    that bud wood taken for propagation was from fruit-bearing branches,    where the thorny juvenility has been outgrown.    -   -   Shape.—Ellipsoid; rectangular in shape.        -   Size.—The average height of trees is 4 meters, measured from            soil level. The average spread (width) of trees is 3.3            meters.        -   Trunk.—The trunk has a smooth surface texture and is            greyed-green (R.H.S. 197A) in color. The average trunk            diameter is 453 millimeters measured at the bud union.            Average diameters of 366 millimeters and 485 millimeters            were measured at heights of 150 millimeters above and below            the bud union, respectively. The average height of the bud            union is 200 millimeters, measured above soil level.        -   Branch.—On average, branches have a circumference of 130            millimeters. There are also, on average, three main branches            per tree, each having an average crotch angle of 55°. As            with the trunk, the branches have a smooth surface texture            and are greyish-brown (RHS 197A) in color.-   Flower:    -   -   Size and color.—The flower of ‘Valley Gold’ is typically            hermaphroditic. Its petals are yellow-white (RHS 158B) on            the inside and yellow-white (R.H.S. 158B) with small yellow            speckles (RHS 8C) on the outside. Further, it has light            yellow (RHS 8C) anthers. Flowering occurs from September to            October in South Africa. Being a normal diploid mandarin,            pollen is abundant and has 66% viability, depending on            climatic conditions, and as determined using the carmine-red            stain method. Flower buds are ovoid in shape and have an            average length of 11.6 millimeters and an average width of            5.8 millimeters. In addition, each flower has five petals.            Petals are elliptic in shape and have an average length and            width of 13.6 millimeter and 6 millimeter, respectively. The            petal tip is acute in shape, while the base is truncate. The            petal margin is entire. On a completely opened flower, the            typical calyx diameter averages 5.2 millimeters. There are            three flowers per cluster and the flowers have a typical            citrus flower fragrance.        -   Reproductive organs.—The style has a length of 7.8            millimeters, while the stigma and the style, in combination,            are approximately 9 millimeters long. The stamen has a            length of 10.6 millimeters. On average, there is one style            and stigma, and 18 stamens with anthers. The style is            slightly longer than the stamen, with the result that the            stigma is more prominent. It has been observed, albeit on a            few rare instances, where the stamens and the styles are            equal in length with the result that the stigma and the            anthers are at the same height.-   Leaves: For purposes of the following leaf description, all leaves    were taken as the first leaf after the new flush growth.    -   -   Shape and size.—Leaves are simple, brevipetiolate and            elliptic in shape, with slightly dentate incisions along the            blade margin. Blade emargination is present at the tip. The            leaves also have typically pinnate venation. The shape of            the leaf apex is acuminate, while the base is typically            rounded. In cross-section, the blade shape is straight or            weakly concave. The length of a typical leaf blade is            approximately 82 millimeters in length and the leaf blade            also has a width of 34 to 44.7 millimeters. The ratio of            length:width of the typical leaf is 2.41:1. The above            dimensions were compared to ‘Clem Late’ (not patented) in a            particular season for comparative purposes. ‘Clem Late's’            leaf blade length was 110 millimeters and the leaf blade was            43 millimeters wide. A further distinguishing feature of            ‘Valley Gold’ with regard to ‘Clem Late’ is that the stalk            attachment of ‘Valley Gold’ is larger than that of ‘Clem            Late’.        -   Petiole.—Wings are present but not prominent and are linear            and narrow. Width of the wings is 1.5–2 millimeters. Length            of the petiole is approximately 8 millimeters. In            comparison, the petiole of ‘Clem Late’ is 10.9 millimeters.        -   Color and surface texture.—The adaxial (leaf upper) surface            is darker (R.H.S. Green 137A to 137B), in comparison to the            abaxial (leaf lower) surface (R.H.S. Yellow-green 146A. The            leaf upper surface is smooth, while Leaf veins are prominent            on the leaf lower surface, which also has a gritty texture            due to the presence of little spots.-   Fruit, external characteristics:    -   -   Color.—The rind color is dark orange and is fairly            blemish-resistant (R.H.S. 28A).        -   Rind.—Fruit is easy to peel and the rind has an average            thickness of 2 millimeters.        -   Oil glands.—Small oil glands are present, slightly pebbled            and protruding and are uniform in size.        -   Surface.—Pubescence is absent on the fruit surface, and the            fruit surface is slightly pebbled in appearance.        -   Shape.—With reference to the Citrus descriptors of the            previously named International Plant Genetic Resources            Institute (IPGRI), now known as Biodiversity International,            the shape of ‘Valley Gold’ is obloid, having its broadest            part in the middle of the fruit. The general shape of the            proximal part of the fruit is slightly rounded, and has a            neck. The length of the neck varies between 2 and 4            millimeters in length and is 12 millimeters thick.        -   Size.—Fruit is on average 47.1 millimeters in length and 60            millimeters in diameter. Individual fruit have on average a            mass of 131.4 grams per fruit (see Table 1 below) on            ‘Carrizo citrange’ rootstock. The fruit length:diameter            ratio is 0.785.        -   Base.—Slightly rounded.        -   Calyx.—Slightly rounded.        -   Apex.—Slightly rounded.        -   Areola.—Present and smooth.        -   Stylar scar.—Present, but small in size.-   Fruit, internal characteristics:    -   -   Color.—The internal flesh color is dark orange (R.H.S. 28A).        -   Navel.—Absent or rare when fruit is viewed internally.        -   Glandular layer.—Thickness of the rag is thin to normal, and            slightly tough.        -   Mesocarp (albedo).—The adherence of the albedo to the pulp            is weak and thus the peel is reasonably easy to remove from            the pulp. Very few albedo strands are left behind after such            removal. The albedo color is yellow-orange (R.H.S. 23D and            19C).        -   Axis.—Fruit has an open core, and a diameter of 14            millimeters. Further, the core has sparse to no filling.        -   Segments.—Each fruit has between eight to ten segments, and            on average there are 9.6 well-developed segments per fruit.        -   Pulp.—Fine with large cells. In a transverse section of the            fruit, the shape of the fruit pulp is scalloped.        -   Juice.—Fruit is juicy with good flavor. Acidity may only            decline to acceptable levels by mid-July and may mask the            flavor in high-acid areas. Fruit have an average juice            percentage of 58.1% and 54.4%, on its own roots and on            ‘Carizzo citrange’ rootstock, respectively. As indicated by            the solids:acid ratio (see Table 1), the best time to            harvest fruit under South African conditions is mid- to            end-July.        -   Seeds.—Seeds are ovoid to semi-deltoid in shape with a            mostly wrinkled surface. In this regard, approximately 20%            of the seed surface tends to be smooth. Further, individual            seeds have an average length of 0.94 millimeters and an            average width of 0.6 millimeters. Furthermore, the seeds            have a grey-white (RHS 155C/D) external color. Seed number            is not excessive in mixed blocks and fruit are commercially            seedless (no fruit has greater than 3 seeds) when caged. In            a highly cross-pollinated scenario, 86.3% (see Table 1) of            the fruit have between 1 and 3 individual seeds per fruit.            Therefore, this selection should be almost seedless in a            solid block although it is probably not self-incompatible.

TABLE 1 ‘Valley Gold’ Mandarin Selections: Averages of Internal QualityTests-2001 to 2006 Addo, Eastern Cape, South Africa Root- Juice BrixAcid Brix:Acid Rind Cultivers stock % % % Ratio Color ‘Valley Gold’‘Carrizo’ 54.4 13.5 1.2 11.6 28 A ‘Valley Gold’ Own roots 58.1 13.1 1.210.7 28 A Percentage fruit with Avg. Fruit Internal 0 1-3 4-6 7+ MassCultives Color seed per fruit (grams) ‘Valley Gold’ 28 A 20.2 65.7 14.00.0 131.4 ‘Valley Gold’ 28 A 1.2 86.3 12.5 0.0 107.3

TABLE 2 Internal Quality Tests (trees planted in 1984): Test Date Juice% Brix % T. Acid % Brix/TA Ratio 28/06/1994 63 12.8 1.15 11.1 11/07/199758 11.2 0.98 11.4 14/08/2002 56 14.4 1.18 12.2 14/07/2004 60 13.0 1.1411.4

-   -   -   Yield.—The average fruit yields across the time period            2001–2007 appear in Table 3 below:

TABLE 3 Average Fruit Yield (2001-2007) Year 2001 2002 2003 2004 20052006 2007 Tree age (years) 4 5 6 7 8 9 10 Yield (kg fruit/tree) 12 26 4551 63 53 55 Yield (ton/ha) 11 24 41 46 57 48 50

The fruit of ‘Valley Gold’ is intended for human consumption. Fruitstored and shipped at 4° C., and kept under these conditions, are likelyto keep for up to 9 weeks (or 63 days).

The above-described new variety of Mandarin displays a distinct lateexpression of maturity (mid-end July), as well as a distinct tougher ragand rind, and a darker external orange color (R.H.S. 28A) as compared toknown varieties.

1. A novel and distinct variety of mandarin tree having thecharacteristics described and illustrated herein.